can water come back up the cold feed c/h header

[iwol]

hi can water actually enter the c/h header tank via the supply feed please and if so why thanks

 

[sonray ltd]

yes for many reasons.

coil in cylinder faulty.
vent pipe blocked.
restriction in system.

 

[iwol]

i know my vents ok how would i check the coil and restriction in system please

 

[sonray ltd]

is the cws tank filling from the ball valve at the same time the f/e tank fills.
(the cws tank shoul be higher than the f/e tank.)

whats the condition of the water in the f/e tank is their sludge in the bottom etc ?
are some of the rads cold at the bottom ?
is it slow to heat ?

 

[iwol]

donnt think the cws tank is filling at the same time
the large cws tank is below the expansion tank(always has been)
water slightly rusty but no sludge just a light coating
rads seem ok
doesnt seem to take any longer to warm than usual
its very difficult because its a slow trickle rather than a gush

 

[sonray ltd]

is it a constant flow in to the tank?
does it only happen when the heating/hw on ?

check the vent pipe isn't drawing in air when system running.

 

[iwol]

cant tell about the flow into the expansion tank as it comes in near the bottom of the expansion tank and this is under water put my finger over the pipe but cant feel anything only the buzz from the pump,dont know if its only when the c/h is on will try that next,

 

[MarkB]

The normal expansion of the system will cause water to flow (expand) back up the feed pipe. My system at home doesn't have a vent, air vents back up the feed pipe, so it's the only route for any expansion flow. It's always been like this since the house was built and it's never caused any problems.

Mark.

 

[justlead1]

Hi. The supply pipe is normally used to describe the main supply into the cistern. i am taking it from your statement the you mean heating cold feed?
If this is the case, yes a proportion of water flows into the cistern when system is heated and back into the system on cooling. That is why the ball valve arm is bent to provide space between water level and overflow, so as the cister does not over flow when system is heated. As a rough formula 25 gallons of water if heated through 99 degrees C would produce a volume of 26 gallons of water. The mass remains the same. Good luck